Réaction #1552134

Équation de réaction

triketo ester

Methyl 3,7,16-trioxo-6α-ethyl-5β-cholan-24-oate

HCl

→

desired compound 9

Rendement 36.4%

Methyl 3α,7α,16β-trihydroxy-6α-ethyl-5β-cholan-24-oate

Rendement 36.4%

Conditions de réaction

Traitement

1. 1
   Températurethe reaction was refluxed overnight
2. 2
   workup.ADDITIONwas added
3. 3
   AutreThe organic layer was separated
4. 4
   Lavagewashed with a saturated aqueous solution of sodium bicarbonate (10 ml), water (10 ml)
5. 5
   Séchagewas dried over anhydrous sodium sulfate
6. 6
   Autreevaporated to dryness
7. 7
   workup.DISSOLUTIONwas dissolved in a mixture 1:4 v/v of H2O/THF (5 ml) and NaBH4
8. 8
   workup.ADDITIONwas added at 0° C
9. 9
   workup.STIRRINGThe mixture was stirred at room temperature for 30 min
10. 10
    workup.ADDITIONwater (5 ml) and 3N HCl (5 ml) were added
11. 11
    ExtractionThe mixture was extracted with EtOAc (4×30 ml)
12. 12
    Séchagethe combined organic layers were dried over anhydrous sodium sulphate
13. 13
    Autreevaporated to dryness under reduced pressure
14. 14
    Autrewas purified by flash chromatography

Mode opératoire

To a solution of the triketo ester 8 (0.1 g, 0.22 mmol) in CH2Cl2 (8 ml) tert-butylamine-borane complex (0.1 g, 1.12 mmol) was added and the reaction was refluxed overnight. The reaction was cooled to room temperature 3N HCl was added and the resulting mixture was stirred for 30 min. The organic layer was separated, washed with a saturated aqueous solution of sodium bicarbonate (10 ml), water (10 ml), was dried over anhydrous sodium sulfate and evaporated to dryness. The residue, in which the 7-ketone was not reduced, was dissolved in a mixture 1:4 v/v of H2O/THF (5 ml) and NaBH4 was added at 0° C. The mixture was stirred at room temperature for 30 min, then water (5 ml) and 3N HCl (5 ml) were added. The mixture was extracted with EtOAc (4×30 ml), the combined organic layers were dried over anhydrous sodium sulphate and evaporated to dryness under reduced pressure. The residue, which consist of at least 2 components, was purified by flash chromatography, using from 1 to 4% MeOH in CHCl3 to yield 0.036 g (0.08 mmol, 36%) of the desired compound 9.

Source